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J. Nick Koston
92106d2a4d
On 32-bit targets, GCC does not optimize 64-bit constant division into a multiply-by-reciprocal and instead calls __udivdi3 (software 64-bit divide). This replaces the division with Euclidean decomposition using a single 32-bit divide that GCC optimizes into a multiply-by-reciprocal. Benchmarked on ESP32 classic (Xtensa LX6, 240 MHz): __udivdi3: 628-705 ns fast_div1000_32: 269-279 ns (2.3-2.6x faster) millis() is called ~21 times per main loop iteration. At ~350 ns savings per call, this saves ~7 us per loop iteration.
